The present invention relates to the production of a fabric having selvages which have been treated to impart ravel resistance thereto.
In the manufacturing of a fabric, it is important that the selvages which extend along longitudinal side edges of the fabric be formed in such a way that they remain intact and do not ravel. When weaving fabrics with traditional shuttle-type looms, this was not a particular problem, since a finished ravel-resistant woven selvage was inherently formed by the inserted weft yarn when the shuttle reversed direction at each side edge of the fabric. However, the newer types of high speed shuttleless looms, such as air jet and water jet looms, form a ragged or fringed selvage which typically must be trimmed from the fabric during the manufacturing operation. This trimmed edge can be subject to raveling during subsequent manufacturing operations and during use.
In some types of fabrics, such as bed sheets and towels for example, the trimmed selvages can be turned under and a hem can be formed along the longitudinal side edges to thereby seal the trimmed edges and prevent fraying. In fabrics where thermoplastic fibers are used, it is also possible that the trimmed edges can be sealed and fused, as described for example in U.S. Pat. No. 4,496,407. In other types of fabrics, if the selvage area is woven tightly enough, the trimmed edge can be left as-is without presenting a significant fraying problem. However, there are many instances where the above techniques cannot be used.
For example, in loosely woven fabrics, the selvages have an increased tendency to ravel. Depending upon the use which is to be made of the fabric, it may not be possible to form a hem along the selvage areas. Fiberglass reinforced composite products, for instance, use a loosely woven reinforcing fabric formed from fiberglass yarns or rovings. The edges of this fabric are subject to raveling during shipment and handling. Woven fiberglass fabrics are also used as reinforcement in printed circuit boards, and these fabrics are typically subjected to a number of handling operations, such as cleaning and/or scouring baths, where raveling is a problem.
With the foregoing in mind, it is an important object of the present invention to provide an improved method for imparting ravel resistance to the selvages of a fabric.
It is a further object of this invention to provide a fabric with selvages which have been treated to impart ravel resistance.
It is still another object of this invention to provide a method of the type described which can form ravel-resistant selvages at speeds which are practical for commercial production.